Galaxy And Mass Assembly (GAMA): improved cosmic growth measurements using multiple tracers of large-scale structure
Galaxy And Mass Assembly (GAMA): improved cosmic growth measurements using multiple tracers of large-scale structure
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DOI：
10.1093/mnras/stt1791
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发表时间：
2013-09
影响因子：
4.8
通讯作者：
C. Blake;I. Baldry;J. Bland-Hawthorn;L. Christodoulou;M. Colless;C. Conselice;S. Driver;A. Hopkins;J. Liske;J. Loveday;P. Norberg;J. Peacock;G. Poole;A. Robotham
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作者：
C. Blake;I. Baldry;J. Bland-Hawthorn;L. Christodoulou;M. Colless;C. Conselice;S. Driver;A. Hopkins;J. Liske;J. Loveday;P. Norberg;J. Peacock;G. Poole;A. Robotham
我们首次将“多重示踪”红移空间失真（RSD）分析应用于观测星系样本，使用来自星系和质量大会（GAMA）调查的数据。我们的数据集是一个r < 19.8等的样本，包含178579个星系，覆盖红移区间z < 0.5，面积180度2。与单示踪剂分析相比，我们从重叠星系群分布中的相关样本方差中得出的引力增长率测量结果提高了10 - 20%。我们提出了星系样本自功率谱和交叉功率谱之间协方差的新表达式，该表达式适用于一般调查选择函数和加权方案。我们没有发现任何证据表明所测量的增长率与所使用的星系示踪剂有系统的依赖性，这证明了RSD建模假设的合理性，并使用来自n体模拟的模拟目录验证了我们的结果。对于由星系颜色选择的多个示踪剂，我们测量了两个独立红移域fσ8(z = 0.18) = 0.36±0.09和fσ8(z = 0.38) = 0.44±0.06的归一化增长率，与标准GR重力和其他类似红移的星系调查结果一致
We present the first application of a ‘multiple-tracer’ redshift-space distortion (RSD) analysis to an observational galaxy sample, using data from the Galaxy and Mass Assembly (GAMA) survey. Our data set is an r < 19.8 magnitude-limited sample of 178 579 galaxies covering the redshift interval z < 0.5 and area 180 deg2. We obtain improvements of 10–20 per cent in measurements of the gravitational growth rate compared to a single-tracer analysis, deriving from the correlated sample variance imprinted in the distributions of the overlapping galaxy populations. We present new expressions for the covariances between the auto-power and cross-power spectra of galaxy samples that are valid for a general survey selection function and weighting scheme. We find no evidence for a systematic dependence of the measured growth rate on the galaxy tracer used, justifying the RSD modelling assumptions, and validate our results using mock catalogues from N-body simulations. For multiple tracers selected by galaxy colour, we measure normalized growth rates in two independent redshift bins fσ8(z = 0.18) = 0.36 ± 0.09 and fσ8(z = 0.38) = 0.44 ± 0.06, in agreement with standard GR gravity and other galaxy surveys at similar redshifts